Simply put, Stumbleupon has no sense of context. My selected interest of "comedy" was so broad I was getting everything from lame puns to dead baby jokes. What finally made me delete it was when I stumbled something called 'dark humor' that was mostly people making violent rape jokes and using the N word more times in a few pages than I'd seen in my whole life put together. A few minutes after that my interest in "video games" directed me to an article by a frothing-at-the-mouth neckbeard literally entitled "$#*! Diversity". Unless this is the sort of content you're interested in I'd give Stumbleupon a miss.